Adds packages/plugin-sandbox: QuickJS-ng compiled to wasm, running in a
dedicated worker, with a runtime shell inside it that loads a plugin bundle
and answers the same InternalEventPayload events the Node runtime answers.
Plugins are unmodified.
Wires the browser host's template function, authentication, cURL import and
template render commands to it, and relaxes TemplateCallback's Send bound on
wasm32 so the engine's renderer can call back out to a plugin.
crates-server/yaak-send-proxy: a stateless executor over yaak-http's
HttpTransaction. It takes a rendered request, streams timeline events,
the response head, body chunks and the resulting cookies back as NDJSON,
and keeps nothing. Private/loopback/link-local/metadata ranges are refused
after DNS on every hop (an AddressFilter on the resolver plus a per-hop URL
check), with size caps, a timeout ceiling, a rate limit, host allow/deny
lists and an optional token.
The web host now sends through it: the wasm worker resolves and renders
the request (render_http_request moved into yaak-models so it builds for
wasm; re-exported from its old paths), the tab posts it, and stores what
comes back where the desktop stores it. Requests needing auth plugins or
template functions are refused with the reason until plugins run in the
browser.